1989 Marathon 2PG Engine Rebuild- In over my head - Please help

[Dave Box]

I wonder if your spark plug has crapped out. It seems to me that when a 2 stroke plug fouls up it seems to just die. A new plug and lead might help.

Dave

[Olman]

Might sound stupid but take the muffler loose and try to crank it.

[racin161]

Right Dave Once it's fouled there is no turning back. Easy check first then choices-choices-choices


LOU

[TexasHunter]

I pulled the flywheel and inspected the position of the pulsar. I believe it is installed in the correct position and aligns with the marks I made when taking it apart. See the attached picture.

I unscrewed the spark plug and held it against the fan cover while pressing the gas and observed the spark is yellow and very intermittent... hence...the poor running.

Can you please guide me on the process to test / troubleshoot the electrical system leading to the spark?

I know I need to test the operation of the pulsar first but I am not sure how to conduct the test. Can you please give a few coaching points on how to do the tests?

[TexasHunter]

Here are a few pictures of the spark plug. It is new and I installed it about 4 days ago. I did not expect it to be so black and dirty after only performing the few attempts to get it running. Can I just buy a new one at a car parts store?

[Olman]

I know you blew by my "muffler post" but if that 25 year old muffler is clogged (and it is hard to tell unless you run it with out it) the engine, if it runs at all, will really run badly. If I'm wrong, I'm wrong but you seemed to have tried everything else.

[cart around]

http://www.ngksparkplugs.com/tech_su...d.asp?mode=nml

This is a pictorial on reading spark plugs. I believe yours is the second one down.

[TexasHunter]

Cart Around- Thanks for the spark plug guidance. I agree mine looks like the second one. I went to Auto zone and got a new one just to be sure. Is there a specific gap measurement that I should confirm on the new spark plug for the 2PG engine before I install it?

Olman- I bought a new muffler last week and expect it to arrive tomorrow. I removed the two bolts connecting the exhaust pipe to the current muffler for my testing. I will have new gaskets and a new muffler but I am planning to continue using the existing exhaust pipe.

Shortly after completing the rebuild, the starter got stuck and would not shut off unless I turned off the key. I cleaned off the micro switch connected to the gas pedal and that seemed to correct that problem. I am thinking I may go ahead and buy a new micro switch and solenoid as part of my trouble shooting. Can a bad micro switch cause the spark plug not to fire correctly? Apologies in advance if that is a naive question - I am getting real time on the job training throughout this project.

I was a bit intimidated by the engine rebuild but I got through that successfully. Now it looks like I will be learning the electrical system as well. I am determined to get this cart running and really appreciate the help.

Any guidance for methodologically troubleshooting the electrical system?

[cart around]

Are you saying that when you took your foot off the gas, the starter would continue to spin, but the engine wouldn't run because the carburetor was closed?

The microswitch, and the keyswitch are wired in series. It takes both of them to make contact for the system to work. It sounds like the contacts in the microswitch were stuck shut. If the solenoid itself was stuck, I don't believe shutting off the key would have made a difference.
The microswitch in the forward reverse switch is the same as the pedal switch. You could swap them. It only connects to the backup buzzer.

[cart around]

http://www.buggiesgonewild.com/attac...n-retrofit.jpg

I believe this should be your wiring diagram.